Abstract: A voltage sharing circuit which allows use of low voltage semiconductor devices to obtain higher output voltages is made up of a series stack of the low voltage devices with diode limiters provided to bias the low voltage devices such that the maximum voltage across any one of the low voltage devices is limited to a predetermined value.

Abstract: A dual-section spatial modulator transmitter consists of a collector surrounding a source of radiation to collect the energy from the source and form it into multiple beams. The collector is configured in two sections, a rotatable section and a stationary section such that spatial modulation is obtained by rotating only the rotatable section.

Abstract: A radiation system consists of a compound collection/beamforming system, surrounding a source of radiation, including an elevation collector/beamformer shaped as a compound parabolic concentrator and an azimuth collector/beamformer shaped so that tangential rays emanating from the source will be collected and formed into a beam of a predetermined design, and a modulator for alternately blocking and unblocking the beam from the compound collection/beamforming system.

Abstract: A device for repeatably and accurately testing an antenna coupler of the type used to connect a test antenna adjacent an onboard antenna of an aircraft to inject a test signal into the aircraft's onboard radar system to test its continuity. A base member is provided with the verification antenna mounted therein. Alignment tabs are provided on the base member for receiving points along the periphery of the antenna coupler. In a preferred embodiment, the base member is mounted inside the lid of a packing case for carrying a plurality of antenna couplers and individual alignment tabs are provided and provided with indicia for properly aligning each of the antenna couplers over the verification antenna. In another embodiment, retractable shielding is provided for electromagnetic shielding of the base member, verification antenna, and antenna coupler during operation.

Abstract: A microstrip tee-fed slot antenna is made up of only a single printed circuit board having the tee feed and slot on the front side and a microstrip transmission line feed on the back side. A plurality of holes in the board surrounding the slot are electrically connected front to back to provide the antenna cavity. Since only a single board is used having all of the components of the antenna on either side, no disassembly is required to add to or modify the elements of the antenna.

Abstract: A system (34) for determining deviations in the state of motion of a projectile (10) from its intended state includes a comparison module (38) that receives the outputs S of a sensor array (36). The comparison module (38) converts the sensor outputs to a measurement vector Z.sub.m and computes the deviation of this measurement vector from an intended measurement vector Z.sub.0 received from a control system. The comparison module (38) then determines the difference E.sub.Z between this measured deviation and the deviation predicted by a Kalman filter (44, 46). In generating the measurement vector Z.sub.m from the outputs of the sensor array (36), the comparison module (38) "de-spins" the array outputs in accordance with the output of a phase reference (42), whose purpose is to indicate the phase with respect to gravity of the spin of the projectile (10) about its longitudinal axis.

Abstract: An adcock DF-on-the-fly type direction finding system employing a beam forming dispersive delay line (BFDDL). A square array of four elements A1, B1, C1, and D1 with A1, C1 and B1, D1 being the diagonal pairs is used to input signals to combiner, shifter and summer elements to produce signals representing S.sub..phi. =A1+B1+C1+D1 and S=(B1-D1)+[(A1-C1) shifted -90.degree.]. S.sub..phi. and S are input to the BFDDL which produces output signals sampled from the output spatial interference pattern of the BFDDL at 90.degree. intervals. The output signals from the BFDDL are used to calculate the arrival of the signal of interest as being substantially equal to the phase shift between S.sub..phi. and S.

Abstract: A test system for microwave circuits such as employed in aircraft wherein a plurality of antennas are connected to a single processor whereby the continuity of the antennas and connectors between the antennas and the processor can be determined. A test signal is applied to the various antennae of the aircraft and the return signals therefrom received by a test antenna disposed in conjunction with a low-loss coupler from outside of the aircraft. An automated test circuit provides for inputting an identifier of the antenna and circuit portion being tested, and for determining the fault location within the circuit as a function of the circuit portion under test and the distance to the fault; and for displaying the fault location within the circuit. In one embodiment, the low-loss coupler includes the use of a plurality of test antennas in combination with a divider circuit connected to the test antennas by transmission lines.

Abstract: A device for determining the frequency range and chirp rate of chirp radars or other sources of frequency-modulated signals includes a compressive receiver (16, 22, 24) for time-compressing single-frequency signals and a discriminator (26) for generating an output that represents the instantaneous frequency of the compressive-receiver output. For narrow-band signals, the frequency-modulated components in the output of the compressive receiver do not last long enough to cause a response from the discriminator (26). When the input of the compressive receiver is a chirp signal, on the other hand, the resultant compressive-receiver output lasts long enough to cause a discriminator response, and its time of occurrence and rate of frequency change are indications of the frequency range and chirp rate of the compressive-receiver input. The discriminator (26) accordingly generates an output whose slope is an indication of the chirp rate of the compressive-receiver input.

Abstract: A simulator for simulating the response of a network of predefined processing elements to a set of input stimuli. The network processing elements are arrayed in a plurality of rows and columns and a representation of each element is stored in a storage location in a symbol memory, the storage locations of which have row and column addresses corresponding to the rows and columns in the network array. A control circuit iteratively receives representations from the symbol memory identifying a processing element at a location in the network and controls an arithmetic and logic unit to generate an output signal representative of the output of the corresponding processing element in response to input stimuli which are represented by data signals from a data memory and an intermediate storage register. The control circuit then controls the storage of the output signal from the arithmetic and logic unit in the data memory and the intermediate storage register.

Abstract: A pneumatic time delay valve primarily adapted for use in the ejection system of electronic or optical countermeasure devices and the like wherein an explosive squib is employed to create a momentary charge of high pressure gas used to depress the firing pin on the device to activate the device and also to push the device out of an ejection tube. The invention comprises means for splitting the pressurized gas into a first conduit communicating with the firing pin and a second conduit communicating with the device to apply the ejection pressure thereon and a time delay valve disposed within the second conduit for delaying the application of the gas to the device. During the time delay period, a piston is forced down a cylindrical bore forcing metering fluid through an orifice.

Abstract: An optical system to permit two detectors to see the same field of view includes an angle converting cone, for mixing radiation from a field of view so that it can be applied to two detectors, and a lens for focusing the radiation onto the cone.

Abstract: A vertically polarized omnidirectional antenna adapted for use in airborne, Very High Frequency (VHF) applications is disclosed. The antenna is configured as a conductive patch spaced over its virtual image. The addition of a number of switching devices allows operation over a five-to-one bandwidth while maintaining a two-to-one Voltage Standing Wave Ratio.

Abstract: The invention concerns an application of linear system parameter estimation techniques to finite amplitude sonar devices, to extract fine grained angular position information about echo sources. The invention makes use of the fact that the waveform return by a reflecting object within the sonar's beam varies according to its relative angular position from the receiver, and a discovery that this variation may be fit to a linear system model using autoregressive estimation theory to extract the nature of the variation. In all cases, the information is extracted without the mechanical or electrical steering of the sonar transmitting beam.

Abstract: A laser which discriminates against a high gain transition in laser materials allowing a low gain transition to oscillate is provided by using more than two mirrors in the laser cavity which are highly reflective at the frequency of the high gain transition.

Abstract: A surveillance system for simultaneously identifying the directions and frequencies of a plurality of electromagnetic-radiation sources includes an irregular array (10) of antenna elements and employs a two-dimensional compressive receiver (14) that receives at its input ports (18) the individual element signals. Each output of the two-dimensional compressive receiver (14) is modulated in an associated modulator (20) by one signal of a composite ensemble of signals. The composite ensemble is the sum of a plurality of individual ensembles, each of which is an ensemble of signals of a frequency uniquely associated with that individual ensemble and individually modulated to favor a direction associated with that individual ensemble. The results are added together in summation circuit 22 and applied to a Bragg cell (24), which segregates the results of modulation by the individual ensembles.

Abstract: A method and apparatus for simulating a network comprising a plurality of processing elements useful in simulating, for example, complex digital combinatorial electronic logic circuits. Each type of digital logic element is assigned a symbol, and the symbols are stored in an array pattern in a memory, with the row and column addresses of the symbols in memory corresponding to their position in the network. The simulator sequentially retrieves each element in the network starting from an input and determines the element response to an input signal based on the type of element and the signals input to it. After all of the elements in the network have been processed, the simulated output of the network is available at the network output elements.

Abstract: An optical power distribution system for supplying power to low power electrical devices includes an electrically powered source of optical radiation the output of which is applied to a photovoltaic cell array arranged on the device to be powered and electrically connected thereto.

Abstract: A cutter assembly (82) for cutting web material such as paper (80) includes a circular cutter (100) having an endless peripheral blade (102) mounted on a frame (92) on which also is mounted a tension roller in the form of a pulley (94). A smaller pulley (98) is mounted on and co-axial with the circular cutter 100, and a belt (96) is trained around the pulleys (94 and 98). The portion of the belt (96) on the tension roller (94) provides an engagement surface adapted to engage the paper (80) so that movement of the cutter assembly (82) causes rotation of the tension roller (94) and thus faster rotation of the circular cutter (100). This results in efficient cutting of the paper (80) and high cut quality because the tension roller (94) prevents bunching of the paper (80) in the vicinity of the endless blade (102).

Abstract: A decimation-in-frequency fast-Fourier-transform butterfly circuit for performing a radix-four butterfly operation includes a first group of adders (86, 88, 90, and 92), a second group of adders (70, 72, 74, and 76), and a group of twiddle-factor multipliers (78, 80, and 82) that are interconnected in such a way as to perform the radix-four fast-Fourier-transform algorithm. Additionally, bypass lines (102, 104, 106, and 108) bypass the first group of adders, and switches (94, 96, 98, and 100) switch between the signals on the bypass lines and those from the first group of adders. As a result, the circuit performs a radix-four FFT operation when the switches are in one state, and it performs two radix-two FFT butterfly operations simultaneously when the switches are in the other state.